Some electronic commerce (E-commerce) systems allow users to purchase goods or services using the Internet or the World Wide Web. For example, a user may utilize a computer to visit an Internet web-site (e.g., Amazon) which provides an online catalog of products available for sale at a pre-defined price. The user selects a product, views a description of the product as well as the product sale price, and adds the product to an electronic (or virtual) shopping cart associated with the user. The user then completes the transaction by paying (e.g., by providing details of his credit card) and by providing a shipping address.
Alternatively, the user may utilize a computer to visit an Internet web-site (e.g., eBay) which provides a service of online auctions. The user selects a product which is offered for auction; views a description of the product as well as the pre-defined terms of the particular online auction; and submits an offer (namely, a bid). Once the auction closes, a “winner” is determined out of the one or more users that submitted bids, and the auctioned item is sold to the winning user.